The present invention relates to a separation membrane cartridge. More particularly, the present invention relates to a separation membrane cartridge and system for creating a desired air mixture for an internal combustion engine.
In recent years, internal combustion engine makers, and in particular diesel engine manufacturers, have been faced with increasingly strict regulatory requirements. Some of these regulations include exhaust emissions, which may take on a number of forms, including visible smoke, particulate matter, and oxides of nitrogen (NOX). As is generally known in the art, particulate matter includes mainly unburned hydrocarbons and soot, whereas NOX is an uncertain mixture of oxides of nitrogen (mainly NO and some NO2).
The formation of NOX may occur when nitrogen mixes with excess oxygen that is not burned in the combustion process. Although excess oxygen and high combustion temperatures are beneficial in reducing fuel consumption, oxygen and high temperatures are detrimental in terms of increased NOX formation. This conflict generally leads engine manufacturers to delicately balance NOX production with brake specific fuel consumption (BSFC) and particulate matter in order to meet emission regulations. One manner of reducing NOX formation within the combustion chamber is through airflow management, which may reduce the amount of oxygen available for formation of NOX.
One known air flow management system, disclosed in U.S. Pat. No. 5,649,517 to Poola et al., introduces an enriched nitrogen air mixture into an engine combustion chamber. A semi-permeable gas membrane separates a portion of oxygen from an intake air flow to create the nitrogen enriched air supply for introduction into the combustion chamber. The system includes an intake line and a secondary line, with the semi-permeable gas membrane cartridge located within the secondary line. The intake line and the secondary line reconnect at a mixing chamber, where the nitrogen enriched air supply from the secondary line is reintroduced to the air in the intake line.
As engines become increasingly complex, the need for efficient use of space within the engine increases. The use of extra air conduits places limitations on the space available for other engine components. Further, extra air conduits may require extra maintenance, and may be more difficult to manufacture than systems with fewer conduits. Furthermore, complex airflow management systems may be difficult to control and operate and, therefore, may be less reliable than less complex systems.
Improvements to the air separation systems are needed so that such systems are more simple, more reliable, more durable, and easier to manufacture, install, operate, and maintain. The present invention is directed at overcoming one or more of the problems set forth above.
According to an exemplary aspect of the disclosure, a separation membrane cartridge is configured to separate an intake air flow of an engine into a membrane flow and a bypass flow. The membrane cartridge includes a fibrous section including a plurality of fibers extending from a first end of the membrane cartridge to a second end of the membrane cartridge. The fibers are configured to separate at least a portion of the membrane flow into a permeate flow and a retentate flow. The membrane cartridge also includes a bypass passage extending from the first end to the second end to allow passage of the bypass flow through the membrane cartridge.
According to another exemplary aspect of the disclosure, a separation system is configured to separate an intake air flow to create a desired air mixture for an engine. The separation system includes a housing having a feed port configured to receive an intake air flow and an exit port configured to output an engine flow. A separation membrane cartridge disposed in the housing may be configured to separate a first portion of the intake air flow into a permeate flow and a retentate flow. The separation system also includes a bypass passage extending through the membrane cartridge from a first end of the membrane cartridge to a second end of the membrane cartridge to allow passage of a second portion of the intake air flow through the membrane cartridge.
In accordance with yet another aspect of the disclosure, a method of creating a desired air mixture for an engine is provided. The method includes receiving an intake flow into a housing, separating a first portion of the intake flow into a permeate flow and a retentate flow, and passing a second portion of the intake flow through a bypass passage extending through a membrane cartridge. The method also includes mixing the retentate flow and the second portion of the intake flow to create an engine flow. The engine flow is outputted from the housing to the engine.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention.